dark secrets from some of america's most beloved celebrities. >> he used to spit on me. he would actually spit on me. >> secrets we'd never believe unless we heard it straight from their own mouths. >> i started waking up in my father's hotel room bed. >> reporter: secrets both shocking and heartbreaking. >> he'd whip all over your face, your back, everywhere. and i'd always hear my mother, no, joe, you're going to kill him, no. >> reporter: whitney houston stunned america when she confessed all to oprah about her drug use with now ex-husband bobby brown. >> you were freebasing cocaine. >> and weed. >> your drug of choice was weed combined with cocaine? >> weed and cocaine. >> and she dropped a lot of bombshells about her life with bobby brown and how emotionally abusive their relationship was. >> we started to paint our room, our bedroom, just eyes, evil eyes, that were looking at every point of the room. >> reporter: but secrets don't get much darker than mackenzie phillips's revelations to larry king about her incestuous relationship with her father, john phillips. >>